Is the risk of osteoporosis increased in myasthenia gravis patients compared with normal people? Let’s take a look at the hints of the recent study of two large samples.
There was no statistical difference in the probability of fractures or osteoporosis-related fractures in patients with myasthenia gravis
A British study published in 2013 conducted a retrospective cohort study of 1066 myasthenia gravis patients from 1987 to 2009, with age and sex-based controls. The results showed that the probability of fracture or osteoporosis-related fracture in myasthenia gravis patients showed no statistical difference compared with the control group, and their adjusted risk ratios (AHR) were 1.11 and 0.98 respectively.
In addition, among myasthenia gravis patients, those who used oral glucocorticoid more than 5 g cumulatively did not show an increase in the incidence of osteoporotic fractures compared with those who did not use hormone, and their adjusted risk ratio (AHR) was 0.99.
However, it is worth the attention of clinicians that, The incidence of fractures increased among patients using antidepressants, antianxiety drugs and antiepileptic drugs. The aHR was 3.27, 2.18 and 6.88, respectively. This study showed that the incidence of fracture did not increase significantly in myasthenia gravis patients compared with age-and sex-matched populations, even in patients using hormones, but in patients taking antidepressants, antianxiety drugs and antiepileptic drugs at the same time, the incidence of fracture increased significantly.
Diametrically opposed research conclusions
However, the results of a larger sample size study published in 2014 from Taiwan’s National Health Insurance Research Database are just the opposite. The study included 2,073 MG patients and set up 6,219 non-MG control groups according to age, sex and storage time.
The results showed that the risk of osteoporosis in MG group was 1.96 times that in non-MG group, and the risk of osteoporosis in MG patients treated with glucocorticoid was higher, with a risk ratio (HR) of 2.37 and that in MG patients not treated with hormone was 1.52. The study also found that compared with the control group, patients aged 30-44 had the highest risk of osteoporosis, with an HR of 2.76.
The study shows that the risk of osteoporosis in MG group is higher than that in non-MG group, but it has nothing to do with whether glucocorticoid is taken or not. It is speculated that it may be related to the patient’s weakness, insufficient sunlight exposure due to reduced outdoor activities, thyroid diseases, etc. It is worth emphasizing that the risk of osteoporosis in hormone-taking group is higher.
Age and ethnic differences
Comparing the two groups of studies, The difference in the results may be largely related to age. The average age of the British study was 60 years old, while the average age of the Taiwan study was 41 years old. The risk rate of osteoporosis in the British study group was 1.7 times higher than that in the Taiwan study group (HR: 1.7). In addition, ethnic differences may also play a role in the two different results.
According to these two studies, we can see that the risk of osteoporosis in young MG patients is significantly increased. Therefore, clinicians need to pay more attention to the risk of osteoporosis in young MG patients. Calcium preparations or drugs that inhibit bone resorption, such as Shuangliendronate, should be added in time when young MG patients use hormone therapy.